1. Field of the Invention
The present invention refers to a distribution device for distributing lubricant to different points of lubrication of a pump device, for instance, said distribution device comprising a casing forming an inner room, an inlet means for the delivery of lubricant to the inner room of the casing and at least two outlet means for the removal of lubricant from the inner room of the casing, said outlet means being connectable to said points of lubrication. Furthermore, the invention refers to a pump apparatus, preferably for producing a subpressure in a milking machine, comprising a pump, having a suction side and a pressure side, and a lubrication device for the supply of lubricant to different points of lubrication of the pump apparatus.
2. Description of the Prior Art
Today, milking machines operated by vacuum pumps are used in barns. In order to be able to guarantee a high and uniform milk production as well as the health of the animals, very high requirements are made on the reliability of these pumps. In order to obtain such a reliability, the lubrication of the pump and especially its bearings is very important.
A usual type of pump device being used today is shown in FIG. 1. The pump device comprises a vacuum pump 1 having a suction side 2 and a pressure side 3 terminating in an outlet tube 4. For the delivery of oil to the bearings of the vacuum pump a so called lubricator 5 is used, which comprises an oil container 6 and in its lower part an oil distributor, not shown. With the aid of the oil distributor, it is possible to guide the oil flow to the bearings via oil conduits 7. On the pressure side 3 of the vacuum pump is provided a silencer 8 and an oil trap 9. Both of them separate oil, which is carried by the air on the pressure side, to a respective container 6a and 6b. The use of this known pump device leads to the following problems. The container 6 provided on the lubricator 5 has to be filled with new oil before it is empty, in order to avoid that the bearings jam. Therefore, continuous supervision of the oil level in the container is necessary. The oil containers 6a and 6b, which are connected to the oil trap 9 and the silencer 8 and which collect the oil separated, also have to be continuously supervised in order to avoid that oil flows out on the floor. The oil flow through the lubricator 5 is controlled by means of a valve directly influencing the oil flow by throttling or opening a passage through which the oil is flowing. The oil amount delivered is very difficult to regulate exactly by means of such a valve. Consequently, this adjustment is done with low accuracy today. Furthermore, the outlets are sensitive to particles of dirt or thickened accumulations of oil, which easily may stop up the outlets. Since the oil flow from the known lubricator 5 may not be observed, it is very difficult to determine how much oil that has been delivered. The oil consumption increases drastically if for example any one of the shaft bearings of the vacuum pump is leaking. Since this increase may not be observed, such a leakage may lead to the breakdown of the bearings. Furthermore, the function of the lubricator 5 is very sensitive to a small inclination of the lubricator, since this results in an unequal distribution of oil to the different oil conduits 7, and thus to the different bearings of the pump. Furthermore, the lubricator 5 demonstrates an open construction, which gives rise to a risk for accumulation of dirt in the oil. Consequently, the bearings may be supplied with impurities. Moreover, the handling of this known lubricating system is relatively complicated, since the new container 6 with new oil has to be provided on the lubricator 5, when the oil in the old container runs out. Moreover, the containers 6a and 6b have to be replaced regularly, since separated oil is collected therein. U.S. Pat. No. 1,092,164 shows an air-tight lubricator for lubrication of an engine, comprising a container for oil and an outlet channel from the container. The known lubricator is provided with a control valve for controlling the amount of air to be supplied to the container. Opening of the control valve results in an increase of the amount of air supplied from the environment as well as of the amount of oil which is delivered from the container to the pump. In the upper portion of the container, there is an opening for filling the container when it is empty. In the lower portion of the outlet channel there is a small window for observation of the flow of oil.
U.S. Pat. No. 899,352 shows a similar air-tight lubricator comprising a container with an outlet tube for oil contained in the container and with a control valve for controlling the amount of air that can be supplied to the container. The control valve comprises an adjustment screw and a loose insertion of silk or cotton, and with the aid of these means the outflow of oil may be controlled in the same manner as in U.S. Pat. No. 1,092,164. In the upper portion of the container there is an opening for filling the container when it is empty.
U.S. Pat. No. 3,507,359 shows a lubricating system for circulating lubricant through the bearings of a machine. The system comprises, except the bearings to be lubricated, an oil sump, a pump, a manifold and a security switch provided to sense the flow of oil and to disconnect the current to the machine when the oil flow decreases below a certain level. The construction of the manifold is not further disclosed.
EP-A-141 573 shows the construction of a reservoir for oil feeded to a bearing, for instance, by means of gravity.
U.S. Pat. No. 1,855,516 discloses a lubricator having a complicated construction and comprising an oil supply container provided with a plurality of oil conduits extending upwardly in the interior of the container and having an inlet for oil normally positioned above the oil level in the container. An oil carrier is slidable along each oil conduit for carrying oil upwardly to the conduit inlet. Means is provided to reciprocate the carrier upwardly and downwardly. By means of an adjustment screw, the height of the upward movement of the oil carrier may be determined, and thus the quantity of oil delivered through the oil conduits may be regulated.
U.S. Pat. No. 3,217,835 discloses a lubricator having a distribution device for distributing a certain amount of oil to different points of lubrication. The distribution device comprises a rotary valve disc rotating with a constant speed and having passages, which will be connected with opposite outlet channels, when they pass said channels during the rotation of the valve disc.